There are a couple that I did not list here, since they aren't commonly seen. I suggest you work on the player and elites ones first, look around the city for various NPCs to click on, and see how it looks before moving further.

IF you are good at using Photoshop, I suggest you look in the folder for all of the FLASH images. These contain the colored borders that flash for combat and aggro status. If you do not edit these, you will be left with a glow around your UFs in the shape of the areas you removed.

As a user of the default UFs, I've tried messing with these images numerous times and have never liked the result. Keep in mind that if you decide to make your own border instead of simply removing them that converting the image from .png to .blp degrades it slightly, so use gradients with care.